Accelerating the search for functional materials is a challenging problem. Here we develop an informatics-guided ab initio approach to accelerate the design and discovery of noncentrosymmetric materials. The workflow integrates group theory, informatics and density-functional theory to uncover design guidelines for predicting noncentrosymmetric compounds, which we apply to layered Ruddlesden-Popper oxides. Group theory identifies how configurations of oxygen octahedral rotation patterns, ordered cation arrangements and their interplay break inversion symmetry, while informatics tools learn from available data to select candidate compositions that fulfil the group-theoretical postulates. Our key outcome is the identification of 242 compositions after screening ∼3,200 that show potential for noncentrosymmetric structures, a 25-fold increase in the projected number of known noncentrosymmetric Ruddlesden-Popper oxides. We validate our predictions for 19 compounds using phonon calculations, among which 17 have noncentrosymmetric ground states including two potential multiferroics. Our approach enables rational design of materials with targeted crystal symmetries and functionalities.

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Learning from data to design functional materials without inversion symmetry.

The effect of Cr{sup 3} substitution on the crystal structure, magnetism, and chemical reactivity of LaSrNiO{sub 4} is described. The phase behavior is discussed.

LaSrCrxNi1-xO4+δ: Crystal Chemistry, Magnetism, and the Stabilization of NiI in an Oxide Environment

Using pure samples of α-Sr2CrO4, an antiferromagnetic (AF) transition was first detected at TN = 112 K by magnetic susceptibility and specific heat measurements. In addition, another transition was observed at TS = 140 K with a clear peak in the specific heat and a small enhancement in the magnetic susceptibility. Despite the two-dimensional crystal structure, the magnetic susceptibility at higher temperatures almost obeys the Curie–Weiss law down to TS. These properties are similar to those of α-Sr2VO4. Electrical resistivity clearly indicates the insulating nature with an electronic band gap of \(\Delta \simeq 1150\) K.

M. Castro

Papers

Phase transitions and magnetic behaviour of R1−xCa1+xCrO4 oxides (RY or Sm) (0⩽x⩽0.5)